Route between subnets.

chuckleberryfin

Hi,
I have a basic Eircom Broadband setup at home, wireless netopia router and a very small LAN. I plugeed a laptop directly into the router and assigned the laptop an IP from a new subnet. The laptop cannot access the internet as the router has an ip from the original (different) subnet. How can I get access to the internet with the laptop on this new subnet? Should I set a static route on the router,laptop or both??

Alun

The obvious question is why you'd assign an IP address from a different subnet at all? What are you hoping to achieve by this?

Just assign it an address from the same subnet that the router is on and save yourself a lot of hassle, or better still just let the laptop get an address via DHCP and be done with it.

chuckleberryfin

Yeah I know, but that's not what I was interested in. I should have mentioned I want to gain access to the internet using the different subnet IP. I'm interested in network configuration and this seemed like a reasonable setup, I'm curious as to how it would work. I'm not sure if I would need to configure an interface on the router for that particular port or if there's a different way. The internet and text books are excellent for theory but the practical aspects seem to be slightly overlooked.

Alun

chuckleberryfin wrote: »

Yeah I know, but that's not what I asked. I'm interested in network configuration and this seemed like a reasonable setup, I'm curious as to how it would work. I'm not sure if I would need to configure an interface on the router for that particular port or if there's a different way. The internet and text books are excellent for theory but the practical aspects seem to be slightly overlooked.

OK, I see ... I'm not that familiar with the Netopia, but in general on el-cheapo consumer level gear like that I'd say you're onto a loser trying to route between Ethernet interfaces like that. They're usually all just connected to a simple 4-port Ethernet switch chip internally.

If you're just looking to experiment, and depending on how adventurous / knowledgeable you are, you could look into getting hold of some second hand Cisco gear, or alternatively if you have an old PC lying around, chuck a couple of Ethernet cards in it and run some flavour of Linux on it.

EDIT: Seems like you can add an additional subnet after all ... see here http://www.netopia.com/support/intl/eircom/technotes/IEQG_028.html This will only allow the PC's on the additional subnet to access the internet, i.e. you won't be able to see any PC's on the one subnet from the other so it's not routing between subnets as such, but it would solve your problem.

chuckleberryfin

Hmm that's almost exactly what I've been thinking. Seems a bit crazy that the router can't route between a different subnet though. Ok, thanks for your help.

chuckleberryfin

That's great, thanks very much! JFGI! Thanks again

Alun

Doing a bit of Googling it seems like I underestimated the humble Netopia routers ... seems like some models at least (possibly depending on s/w version) support VLAN's and routing between them ...

See http://www.netopia.com/support/hardware/technotes/CQG_146.html

Don't have one myself (I have a Cisco 877W) so can't test it out, but it looks promising.

Some_Person

If you add a route you put in the destination IP and the subnet mask but then you'd have to add a route for each IP, next best thing to routing to the whole subnet.

Snaga

Theres a simple rule here.

If you want a router to route between two connected ip subnets, then the router has to have an interface* in both IP subnets. (* Physical or logical interface).

NullZer0

You can do this with the stadard Netopia router supplied by Eircom.
In the advanced configuration settings you can configure ports as "access ports" in different VLANS and assign subnets to the VLANs.

The router will then route between the VLANs (I'm guessing it uses IEEE802.1Q).


HTH